1. Field of the Invention
The present invention relates to a camera (e.g., a conventional camera using sensitive film, a hand-held video recorder, or a digital camera), having a control dial through which a display panel can be viewed.
2. Description of the Prior Art
A camera which is provided on a camera body thereof with a control dial (e.g., a mode select dial) through which a display panel (e.g., an LCD panel or an LED panel which is surrounded by the control dial) can be viewed, is known in the art. FIG. 11 is a perspective view of such a combination of a control dial 101 and an LCD panel 102 on the top panel (not shown) of an SLR camera. The control dial 101 is manually turned to select, e.g., an exposure mode from a plurality of exposure modes including a manual photometering mode, an aperture-priority auto-exposure mode and a programmed auto exposure mode. As can be seen in FIG. 11, information indicated by the LCD panel 102 is read through a circular transparent window plate 103 fitted in the center opening of the control dial 101. The LCD panel 102 indicates, e.g., information corresponding to the rotational position of the control dial 101.
The control dial 101 is provided with a switching protrusion 104 which protrudes downward from an outer periphery thereof. The protrusion 104 turns ON and OFF a plurality of switches 105 (only one is shown in FIG. 11) which are arranged on a circle the protrusion 104 moves, upon rotation of the dial 101. A plurality of pins 106 prevent the dial 101 from detaching from a camera body. The rotational position (rotational angle) of the control dial 101 is detected by the switches 105 which are turned ON by the protrusion 104 when the dial 101 is rotated.
In such a control dial, the rotational position thereof can be detected only at wide intervals, and therefore cannot fill the needs of providing the control dial with many detectable rotational positions with fine precision. FIG. 12 shows a combination of a control dial 201 provided on an external panel 205 and a display panel 202 of another conventional camera which provides a solution to the above-described problem. In this example, a code plate 204, which has a predetermined conductive code pattern (not shown) printed thereon, is fixed to a frame 206 of a camera body, and a brush 207 having a plurality of electrical contacts which come in sliding contact with the conductive code pattern of the code plate 204 is fixed to an inner peripheral portion of the control dial 201. The rotational position of the control dial 201 is detected via the brush 207 and the code plate 204. The display panel 202 is mounted onto the center of the code plate 204 so that information indicated by the display panel 202 can be read through a transparent window plate 203 fitted in a circular opening formed in the center of the control dial 201.
In the control dial 201, since the brush 207 is positioned inside the control dial 201, the display panel 202 has to be small so as not to interfere with the brush 207; however, this does not allow for a large display panel.
FIG. 13 shows a conventional mechanism wherein the control dial 201 has a clicking action upon rotation thereof, which prevents the control dial from rotating unintentionally. Namely, a click mechanism is provided on an outer peripheral face of the control dial 201 with a plurality of notches 301, and is further provided with a steel ball 303 which can be engaged in each notch 301, a compression coil spring 302 which normally biases the steel ball 303 against the outer peripheral face of the control dial 201, and a screw 304 which is screwed into a radial through hole formed in the external panel 205 to hold the compression coil spring 302 and the steel ball 303 between the screw 304 and the outer peripheral face of the control dial 201.
In such a mechanism, a space for arranging the compression coil spring 302 and the steel ball 303 is required and at the same time a device including the screw 304 for preventing the compression coil spring 302 and the steel ball 303 from coming out of the through hole accidentally is also required, which complicates the structure of the mechanism.
The present invention has been made in view of the aforementioned problems described above, and accordingly, an object of the present invention is to provide a camera having a control dial through which a display panel can be viewed, wherein the rotational position of the control dial can be detected at close intervals with fine precision, and wherein the display panel, which is surrounded by the control dial, is large.
Another object of the present invention is to provide a camera having a control dial and a display panel, wherein the camera is provided with a simple mechanism which provides the control dial with a clicking action, upon rotation thereof, which prevents the control dial from rotating unintentionally.
To achieve the objects mentioned above, according to an aspect of the present invention, a camera having a control dial/display panel unit is provided, the control dial/display panel unit including a ring member which can be manually rotated about a first axis; a display panel which is surrounded by the ring member so as to be viewed through an aperture of the ring member from outside the camera; a rotational member which is rotatable about a second axis which is inclined with respect to the first axis; a transmission device for transmitting the rotation of the ring member to the rotational member; a detection device which is disposed on the rotational member to detect rotation information of the rotational member; and a controller which determines rotation information of the ring member via the rotation information of the rotational member, which is detected by the detection device, to indicate information corresponding to the rotation information of the ring member on the display panel.
Preferably, the rotation information of the ring member includes information on a direction of rotation of the ring member.
In an embodiment, the rotation information of the ring member includes information on a rotational angle of the ring member.
In an embodiment, the rotation information of the ring member includes information on an absolute rotational angle of the ring member.
Preferably, a transparent window plate is further provided, which is fitted in the aperture of the ring member.
Preferably, the display panel has a polygonal shape including at least eight sides, the perimeter of the display panel being positioned closely to an inner peripheral surface of the ring member without coming in contact therewith.
Preferably, the transmission device includes a first gear formed on an inner peripheral surface of the ring member, and a second gear which is formed on an outer peripheral surface of the rotational member to be in mesh with the first gear.
The detection device can include a code plate having a predetermined conductive code pattern, the code plate being mounted to the rotational member, and a brush which comes into contact with the predetermined conductive code pattern.
Preferably, the control dial/display panel unit further includes a plurality of notches formed on an inner peripheral surface of the ring member, a support which supports the display panel, a hole formed on the support, a ball positioned in the hole, a biasing member positioned in the hole to bias the ball toward the inner peripheral surface of the ring member so that the ball can be engaged in one of the plurality of notches with a click, and a brush holding member which holds the brush. The support includes an insertion opening which communicatively connects with the hole so that the ball and the biasing member can be inserted into the hole via the insertion opening. The brush holding member includes a protrusion which is engaged in the insertion opening to prevent the ball and the biasing member from coming out of the hole via the insertion opening.
The biasing member can be a compression coil spring.
Preferably, the ring member, the rotational member and the detection device are mounted to an external cover of the camera.
Preferably, the second axis is inclined with respect to the first axis by an angle one of greater than and equal to 25 degrees and one of less than and equal to 35 degrees.
In an embodiment, the first axis is inclined with respect to a vertical direction of the camera.
In an embodiment, the second axis extends in substantially a vertical direction of the camera.
Preferably, the display panel is an LCD.
Preferably, the rotational member is in the shape of a disc.
Preferably, the control dial/display panel unit further includes a click mechanism which provides the ring member with a clicking action upon rotation thereof which prevents the ring member from being rotated unintentionally.
In an embodiment, the display panel has an octagonal shape.
Preferably, the brush holding member is fixed to the support, and the rotational member is mounted to the support via the brush holding member.
Preferably, the plurality of notches are formed on the inner peripheral surface of the ring member at equi-angular intervals.
Preferably, the brush holding member is fixed to a bottom surface of the support.
The control dial/display panel unit can further include a rotational cylinder to which the rotational member is fixed; wherein the brush holding member includes a pivot on which the rotational cylinder is fitted to be rotatable about the pivot.
In an embodiment, the ring member includes a first gear formed on an inner peripheral surface of the ring member, and the rotational member includes a second gear which is formed on an outer peripheral surface of the rotational member to be in mesh with the first gear. The plurality of notches can be formed along a circumference of the ring member above the first gear.
According to another aspect of the present invention, a control dial/display panel unit is provided, including a ring member which can be manually rotated; a display panel which is surrounded by the ring member so as to be viewed through an aperture of the ring member from outside the camera; a rotational disc positioned below the display panel obliquely to the ring member; a transmission device for transmitting rotation of the ring member to the rotational disc; and a detection device which detects information on rotation of the rotational disc. The display panel indicates information corresponding to rotation information of the ring member which is determined via rotation information of the rotational disc which is detected by the detection device.
The present disclosure relates to subject matter contained in Japanese Patent Application No. 2000-226797 (filed on Jul. 27, 2000) which is expressly incorporated herein by reference in its entirety.